This is basically what I'm getting after trying to add repositories so that I can add lenses. Any help would be greatly appreciated.

W: Failed to fetch cdrom://Ubuntu 12.04LTS _Precise Pangolin_ - Release amd64 (20120425)/dists/precise/restricted/binary-amd64/Packages
Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs
W: Failed to fetch http://ppa.launchpad.net/jsevi83/unity/ubuntu/dists/precise/main/source/Sources 404 Not Found

There's more that I'm guessing aren't too dubious. Very similar to the others. Again, any help would be appreciated.